There is an old argument, how they ae created? If an Archdemon blood is needed for the Joining..
i. who kill the first Archdemon to get the blood?
ii. how do they know they need the blood?
iii. how they defeat The Blight without being Grey Wardens?
iv. when do they realized they need the blood for the Joining?
v. who was the first Grey Warden?
vi. how many try and error failed before they get it right?
The world nearly anihilated as the history says, but suddenly there are Grey Wardens who save the day....there is something fishy about it, like it is all have been planned from the begining. The Blight is planned, the creation of Grey Wardens also planned.
They need Mages to prepare for the Joining anyway....in Ostagar only 7 Mages was there...i am not sure Duncan mention the Circle Mages or Grey Warden Mages, i don't see any Grey Warden mages in Ostagar, if it was Circle Mages then the Circle Mages know how to prepare the blood for the Joining...this even make "there is something wrong somewhere..."